For Baha al-Deen Muhammad, an entrepreneur turned rebel in northern Syria, and Khalid, a young man stuck in the devastated central city of Homs and running low on both food and hope, the official start of a supposed UN-brokered withdrawal brought precisely no improvement to their lives.

For Khalid, the 6am deadline was marked instead by the beginning of a two-hour barrage of shelling from Syrian government forces around the city. Muhammad was spared a renewed military bombardment of Hazanu, his small home town near the city of Idlib, but he too remained trapped, his home destroyed, family exiled elsewhere and supplies also dwindling.

Khalid used the camera on his Skype-connected laptop to remotely lead the Guardian on a makeshift tour of Dourat al-Shiyah, a central district of Homs, the rebel stronghold that has suffered most acutely in the crackdown by the regime of President Bashar al-Assad that has killed an estimated 9,000 people over the past 13 months. He has been living there since his nearby home district, Bab Saba'a, was occupied by the military. As a known activist his home was burned down.

Moving the camera between his own gaunt, slightly bearded face and the scene around him, Khalid showed the skeleton of a burnt-out car, a snapped electricity pole – deliberately targeted, he said, to deprive residents of power – and then a large block of flats, now half-hollowed out by shells, some balconies shot away, and abandoned.

"They want everyone to leave Homs, because if everyone leaves then there is no one here who can protest against the regime. We have had no supplies of food for three days," Khalid said. Behind him, occasional pick-up trucks roared past, filled with more fleeing families. Even this, he said, was not always a safe option: "If they are stopped at a checkpoint the army will look for activists. Often they will take all the men, leaving just the women and children." In many areas, he said, only the old were left.

Just further along the rubble-strewn street, he paused. "If I go any further I could be shot by snipers," he said. "Over there are 20 decomposing bodies. We can't move them because of the risks." A gunshot wound of almost any type is likely to lead to death, Khalid added: "We only have one hospital remaining, and we can't get to it because of the snipers."

Neither Khalid nor Muhammad said they were surprised at the failure of the government or Syria's makeshift rebel forces to observe the peace plan, negotiated by Kofi Annan. On Tuesday the former UN head visited one of the many refugee camps that have sprung up along the Turkish border, where thousands of Syrians have fled the violence sweeping the country. Hundreds of refugees greeted him with chants of "Syria, Syria, Syria!"

Annan said his peace plan was still alive. "I believe it is a bit too early to say that the plan has failed. The plan is still on the table," he told reporters.

But in Muhammad's case his words fell on deaf ears. "We don't want a dialogue with this regime," Muhammad said. "We only want to see the end of this regime. I can't forget the memories of the slaughter of the last year, or the repression of the last 40 years."

The 32-year-old businessman, speaking via Skype from the house in Hazanu where he has been sheltering since his own was destroyed last week, said the military were still in place nearby. "There are still checkpoints surrounding the town. If I tried to pass one of these checkpoints they would certainly detain me and I am pretty sure they would kill me. I sent my wife and children away three months ago and I have not seen them since. They are not far away but I would not make it."

Last week, Muhammad said, he and others fled to nearby hills as the military moved into Hazanu. Watching from a distance he counted more than 70 tanks and 15 trucks carrying artillery. A subsequent bombardment, also involving three planes, destroyed dozens of houses.

After three days, he said, the military withdrew and he returned to find his home and that of his brother among those razed, with food shops and pharmacies destroyed or ransacked, along with the town's small hospital. He learned that 25 residents were now missing.

"We do not know what has happened to these people, only that they are no longer here. We assume they have either been detained or killed," he said.

There is no way to verify Muhammad's account of events, and as a self-proclaimed member of the Idlib region's "revolutionary command" he is a far from unbiased voice. However, his account tallies with wider reports of Syrian army aggression and alleged atrocities around Idlib. On Tuesday, Human Rights Watch detailed a series of alleged recent atrocities, including the killing of at least 13 men at a mosque in the city last month.

Muhammad's wife and three children, aged seven, six and two, have fled to another nearby city, Aleppo. He is able, very occasionally, to speak to them on Skype but he does not know when, or how, he can see them again.

Conditions in Hazanu meanwhile, he added, are getting worse all the time. While he is still occasionally sent money from a company he part-owns, others on government lists of known dissidents have lost their wages. "Some people have been selling their possessions to survive, but now they cannot even do that if their house has been destroyed," he said. "They are being forced to rely on help from other people to survive."

Despite the appalling hardships he is resisting temptation to put hope in another external peace plan: "I don't trust the government at all with a ceasefire," Muhammad said. "We can't have any sort of ceasefire without knowing what happened to all the people from the town who disappeared. The government is playing for time, so it can kill as many of its opponents as possible before it is stopped."